1. Field of the Invention
The present invention relates to a light source device and a projector.
2. Description of Related Art
A Projector that modulates a light beam irradiated by a light source in accordance with image information and projects an optical image in an enlarged manner has been widely used, together with a personal computer, for presentation in meetings, academic conferences, exhibitions, or the like. In recent years, it has been used for at-home-movie-viewing.
As a light source device of the projector, a light source obtained by fitting a reflector to a light-emitting tube such as a metal halide lamp, a high-pressure mercury lamp, or halogen lamp is used. An electrical continuity between the light-emitting tube and an external power source is made by a lead wire welded to base caps of sealing portions disposed on both sides of the light-emitting tube.
As disclosed in Jpn. Pat. Laid-Open Publication No. 2003-132702 (see FIG. 5 and the like), a light-emitting tube projects in a reflector. In this document, in order to draw a lead wire extending from the sealing portion on the projecting lead end out of the reflector and fix the drawn out lead wire to the reflector, for example, a configuration in which the lead wire is inserted through a hole formed on the reflector and the lead wire is fixed by a metal fitting at the hole portion has been adopted.
In the case where a front glass for preventing the scatter of broken pieces of the light-emitting tube upon burst of the same is provided, a configuration in which the lead wire is pinched between the edge portion of the front glass and opening edge portion of the reflector and fixedly bonded is employed to draw a lead wire extending from the sealing portion on the projecting lead end out of the reflector and fix the drawn out lead wire to the reflector.
Further, to draw out and fix the lead wire, a configuration like a light source lamp unit 10′ shown in a sectional side view of FIG. 6 has been employed, for example. More specifically, in this light source lamp unit 10′, a lead wire 200′ extends from a fastener 116 of a first sealing portion 112 toward an opening edge portion 125 of an ellipsoidal reflector 12 and further extends toward the outside of the ellipsoidal reflector 12 in such a manner to cross the peripheral edge of the opening edge portion 125. The drawn out lead wire 200′ extends along the periphery of the ellipsoidal reflector 12 and is fixed.
In any of the above configuration, the lead wire is fixed to a connection terminal to be connected to an external power source by welding or the like, the connection terminal being disposed near the reflector.
However, in the configuration of the above document, a hole or the like must be drilled in the reflector, decreasing an amount of the reflected light of the light source by the area corresponding to the hole. This reduces light utilization efficiency, thereby resulting in illumination loss.
In the case where the sealing portion projects beyond the reflector opening, the front glass cannot be provided depending on the shape of the light-emitting tube or reflector, in some cases. In this case, it is difficult to fix the lead wire to the reflector. If the lead wire is not fixed to the reflector reliably, the lead wire has possibility of falling off from the welding portion when, for example, the lead wire is connected to the connection terminal for an external power source. Specifically, when the lead wire may be pulled or pushed and contracted, a certain load is applied to the welding portion of the lead wire at the distal end of the sealing portion, whereby the lead wire to come free from the welding portion, as often as not. In addition, the possibility that the light-emitting tube is broken or damaged by the applied load occurs to decrease built-in characteristics or reliability of the light source device. That is, there has been a need to realize a mechanism for reliably fix the lead wire even in the case where the front glass or the like is not used.
In the wiring of the lead wire 200′ of the light source lamp unit 10′ as shown in FIG. 6, the lead wire 200′ is not fixed to the ellipsoidal reflector 12. Accordingly, the lead wire 200′ tends to be displaced at the opening edge portion 125 of the ellipsoidal reflector 12, or tends to slip off the opening edge portion 125, making it difficult to perform the wiring work of fixing the lead wire 200′ to a terminal block. Further, during the wiring work, if the lead wire 200′ is pulled, or conversely, pushed and contracted, a certain load is applied to the welding point on a fastener 116 of the distal end of the first sealing portion 112, with the result that the lead wire 200′ may slip off the fastener 116 or the light source lamp 11 may be broken or damaged.